What California’s Strict New Vaccination Law Means for the Rest of the Country

California’s Gov. Jerry Brown signed into law Tuesday a controversial bill that imposes one of the strictest school vaccination laws in the country.

The law, which will go into effect for the 2016-17 school year, not only wipes out the state’s personal-belief exemption, but it also rules out parents’ ability to refuse to vaccinate their children for religious reasons — which was part of the personal-belief exemption. The law encompasses most forms of schooling in the state, including public and private schools, as well as daycare facilities.

Now, California parents who are opposed to vaccinating their children have two options: Obtain a medical exemption (designed for children with serious health issues) or homeschool their children. For the medical exemption from the measles, mumps, and rubella (MMR) vaccine, children must have had a life-threatening allergic reaction to the antibiotic neomycin or another component of the vaccine, or have actually fallen ill in the past from measles, mumps, or rubella.

The strict new law comes in the wake of an outbreak of measles at Disneyland in December. According to the Centers for Disease Control and Prevention, there were 178 reported cases of measles from January to June 2015, 117 of which were linked to the Disneyland outbreak.

Illinois, Washington, Arizona, and Nevada have also had five or more measles cases since January.

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From January 1 to June 26, 2015, 178 people from 24 states and the District of Columbia were reported to have measles. (Image: CDC)

The vaccination landscape in America

According to data from the National Conference of State Legislatures, West Virginia and Mississippi are the only other states without a personal-belief or religious exemption for vaccines, allowing parents in the majority of U.S. states to refuse to vaccinate their children — at least under religious grounds. Twenty states also allow philosophical exemptions for those who object to immunizations due to personal, moral, or other beliefs.

Public law expert Dorit Reiss, a professor of law at the University of California, tells Yahoo Health that this new law can make a big difference for the state of California. “Overall we have high vaccination rates, but there are some communities in which 50 percent or more have used vaccination exemptions,” she says. (Research published earlier this year in the journal Pediatrics found that unimmunized children typically live in clusters, often in wealthy communities.)

Current data from the California Department of Public Health found that more than 5 percent of private-school kindergarten students in the state used a personal-belief exemption, compared to 2.3 percent of public school students.

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Estimated percentage of children enrolled in kindergarten who have been exempted from receiving one or more vaccines and states with less than 90 percent coverage of children with two doses of MMR vaccine during the 2013-14 school year. (Image: CDC)

Those communities where large groups of children are not immunized run a high risk of contracting vaccine-preventable diseases like measles, says Diane Peterson, associate director for immunization projects at the Immunization Action Coalition. “In order to prevent the spread of disease, you need a very high vaccination rate,” she tells Yahoo Health, pointing out that parents who don’t vaccinate their children often rely on other children to be vaccinated. “When you only have 50 percent of children vaccinated, that is ripe for an outbreak.”

California isn’t the only state struggling with vaccination rates

According to nonprofit health policy organization Trust for America’s Health, less than 90 percent of children aged 19 to 35 months have received the recommended vaccination against measles, mumps, and rubella in 17 states. (The national vaccination average among that age group for MMR is 92 percent, per the CDC.)

Colorado, Ohio, and West Virginia have the lowest vaccination rates for MMR at 86 percent, according to the National Immunization Survey, while no state in the Northeast is below 90 percent. (New Hampshire has the highest MMR vaccination rate for preschoolers at 96.3 percent.)

Colorado’s vaccination rate isn’t improving with age. The CDC reports that less than 82 percent of children in Colorado have been vaccinated by the time they reach kindergarten.

Now, some states are taking action

In 2015, at least 12 states have considered or are considering legislation that will address immunization exemptions. Vermont was the first state to repeal its personal-belief exemption (but still has an existing exemption for parents to opt out of immunization due to religious beliefs). Illinois, South Dakota, and West Virginia also passed laws this year related to exemptions.

Oregon has pending legislation that would require a schedule for exemption submissions and Washington is considering a bill that would eliminate the personal-belief exemption.

Legislation introduced around the country is pulling in two different directions, says Wendy Parmet, director of the Program on Health Policy and Law at Northeastern University.

Some states are making it harder to avoid vaccination — while others are making it easier

“Bills pending in many states make it harder for state exemptions, and many states are looking at adding procedural hurdles for exemptions to make them not quite as frictionless as they have been,” she tells Yahoo Health. “Others are looking to broaden their exemptions. Legislatures are simply reflecting the views of the population.” One bill in New York, for example, would have established a personal-belief exemption.

While the latest law was passed in California, experts say it may inspire like-minded legislation in other states.“In the past, California has been the leader in many legal areas, and this may set an example,” says Reiss. “But it’s never easy to pass a bill on vaccination requirements, since the opposition is usually so intense.”